Smelting furnaces



o. F. swENsoN 2,940,744

SMELTING FURNACES 3 Sheets-Sheet l June 14, 1960 Filed Feb. 1o. 1958 June 14, 1960 o. F. swENsoN SMELTING FURNACES 3 Sheets-Sheet 2 Filed Feb. l0. 1958 O. F. SWENSON SMELTING FURNACES June 14, 1960 3 Sheets-Sheet 3 Filed Feb. 10. 1958 United States Patent Oiiice SMELTING FURNACES OscarFrederick Swenson, deceased, late of South Pasadella, Calif., byWalter L. Engelhardt, administrator, 653s. Lake St., Pasadena, Calif.

Filed Feb. 10, 1958, Ser. No. 714,441

6 Claims. (Cl. 263-39) This invention relates to improvements in smelting furnaces of the type employed to melt pig iron, cast iron scrap, steel scrap, ironor iron ore concentrate briquettes and the like.

The application may be considered as a continuationin-part of the application on Smelting Furnaces filed August 13, 1956, Serial No. 603,595, now abandoned.

'Ihe above-mentioned application discloses a smelting furnace consisting. of two smelting chambers arranged in end to end relationship and in communication with each other at their inner ends. At the outer ends of the chambersV there are heating means in the form of oil burners and a duct connects the outer ends of the chambers to each other and to a stack. When one chamber isused as a smeltingfurnace the oil burner in the outer end thereof is utilized. Theother chamber is used as a pre-heater, the intention being that the heat derived from the oil, burner be utilized to melt the material in the smelting chamber and that the products of combustion pass therefrom into the other chamber and be utilized to preheatV the material thatis disposed therein and which is ultimately tobe melted.

Afterl passing throughthe pre-heating chamber the hot gases-discharge into the duct and are carried therethrough to theV outer end of the melting chamber, excess gas beingreleased through the stack. When the contents of theV melting chamber have been melted and poured the pre-,heatingchamber is then utilized as a melting chamber `and theoil burner in the outer end thereof is then utilized to bring its contents to a molten condition. The chal ber that was previously used as a melting chamber is then charged with material and is used as a pre-heating chamber. The direction of flow of hot. gases through the two chambers `andthrough the duct is reversed.

The :relatively long passage through the chamber that is utilizedas a pre-heatingchamber and through the return duct causes the hot gases which reenter the melting chamberA to be sufficiently cooled that the utilization of theavailable heat derived from the burner is somewhat limited.

It is an object of the present invention to pro-vide an improved furnace having generally similar characteristics inthatthere are two melting chambers arranged in end to end relationship and in communication with each other withburners applicable to the outer ends of each chamber.H However, instead of causing all of the products ofv 'combustion produced in the melting chamber to pass through the pre-heating chamber and then to be returned through a relatively long duct, these hot gases are caused to flow a divided path or paths. A substantial portion ofthehot gases developed in the melting chamber are immediately returned to the outer end of the melting chamber through `a relatively short return duct so that these hot gases at the time they reenter the melting chamber, are quite hot and can be advantageously used to assist in melting the contents of the melting chamber and contribute to themaintenance of a reducing atmosphere therein. Only a portion of the hot gases discharged required to be returnedthereto and over the amount required to pass, throughthe pre-heating chamber to preheat its contents, the excess of gases are permitted to pass directly to the stack. With this arrangement, the available heat, derived'from the burner is most advantageously utilized, contributing to a Very efficient furnace that can be used to melt scrap and/or to reduce iron ores.

With` the foregoing and other objects in View, which will be made manifest in the following detailed description and specifically pointed out in the appended claims, reference. is had'to the accompanying drawings for an illustrative embodiment ofthe invention, wherein:

Figure 1 is a top plan View of the improved smelting furnace embodying the present invention;

Fig. 2 is a vertical section talren substantially upon the line 2-2 upon Fig, 1 in the direction indicated; and

Figs. 3, 4, and 5 are vertical sections taken substantially upon the linesS-S, 4 4, and '5-5, respectively, in the directions indicated upon Fig'. l.

Referring to the accompanying drawings wherein similar reference characters designate similar parts throughout, the improved furnace consists of twol somewhat barrel-shaped chambers wand 11 formed of any suitable material andV preferably linedwith refractory material. These chambers are arranged in alignment and in end to end relationship, and may be regarded as-coaxially arranged on oppositesides of a central partition 12 between them. The exteriors of the chambers are equipped withrcircurnferentially extending rails 13 which roll in grooved supporting rollers 14, see Fig. 4, and enable each chamber to be-rotatably oscillated and to be tilted independently of 'each other. As a means forrotatably oscillating`v the chambers there is illustrated a hydraulic ram `15 `connected as at 16 for each chamber, and this-hydraulic-ram has the uid supplied to and exhausted from its cylinder by means of an electric valve, not shown.

When end chamber 10er 11 is being utilized as a melting chamber its ram 15 is caused to reciprocate either continuously or periodically so that the molten contents of the chamber will have its corrosive effect on the refractory lining distributed over the interior surface. When the contents of the chamber is molten it may be poured from the chamber through a pouring spout 17 in which case, the hydraulic ram is actuated beyond the length of stroke required for reciprocation and rotates the chamber into a position wherein the molten contents can be poured from the pouring spout. Charging doors 18 are arranged in the sides ofthe chambers horizontally opposite the pouring spouts and the chambers are charged with the material that is to be melted therethrough.

At the outer ends of the chambers 1t? and 11 there are end wallsl and19a in which there are formed passages 29 and 214that arecoaxially arranged with respect to the chambers 10 and 11. The outer ends of these passagesmay have positioned therein heating means in the formof oil burners V22 and23 which discharge llame and products of combustionY through their respective passages 26 or 21 into their respective chambers 1t? or 11. It will be understood, however, that when burner 22 is in positio'nand is being utilized to melt the contents of chamber 1i) -=that chamber 11 is used as a pre-heating chamber, in which case ,burner 23 is removed and is replaced bya door, not shown. Conversely, if chamber 11 is being used asia-melting chamber and chamber'l-is being used as a pre-heating chamber, the oil burner 23 Patented- June 14,l 1,960.;

' foundation Yfor the furnace.

, purpose. is closed but valve 34Vwhich controls exhaust duct 32 is.

l 3 r is in'applied position and burner 22 is removed and is replaced by a door, not shown. Y

' 24Vand 25 are hollow water-cooled rings having muexist between the ends ofthe chambers 10 and V11'and the end walls V19 and 19a and the partition 12, the inter- Yfitting engagement between the water-cooled rings 24 andV 25 Vtends to confine flame and hot gases against escaper even though the chambers oscillate relatively to the stationary end walls and partition. L

In the partition 12 there'is formedV a passage 27 that is coaxially arranged with Vrespect to the chambers and iiow through this passage is regulated by a water-cooled gate Valve or the equivalent, indicated at 28. Each chamber and 11 has in association therewith a return duct identified by thereference characters 29 and 30,respectively. A portion .ofeach return duct is formed in the central partitionr12 and extends through lthe supporting Each return duct terminates inthe end wall 19 andj19a, respectively, and com# Vmunicates with thepassages 20 and 21', respectively, in

the manner illustrated in Fig.. 3. Each return duct 29 and 30 has in communication therewith a branch exhaust 'Y duct, these'ducts being indicated at.31 and'32, respectively. Vl-Tlow. through these exhaust ducts is'icontrolled orrregulatedV by water-cooled valves 33"and.34,' respec-l tively. These ducts lead to a stack 35 and'ow into the stack is regulated Vby awater-cooled valve 36. Addi-V Y tional exhaust ductsV 37 Vand 38V lead from the passage 27 in theV partitio'n 12 on opposite sides of the valve 28 to 1 valves 39 and 40, respectively.

, The operation and advantages of the improved furnace are substantially'as follows: e 'i YAssuming that both'chambers, 10 and 11 haveV been vcharged with material to be melted and that chamber 10 the stack 35.' These ducts are regulated by Water-cooled ,Y is' initially the melting chamber, burner 22 isapplied to Y end Wall 19 and burner 23 removed and replaced by a Y hot gases impart heat to the charge in chamber 10Vand coo'perate with the heat generated by the burner 22 in bringing the charge in chamber 10 up to molten condition. They also contribute .to the maintenance of a reducingV atmosphere in chamber 10., There is an excess ofV gases. deliveredeor supplied to passage 27 over and that required to pass through chamber 11 for pre-heating purposes.. This excess of hot gasesis permitted to pass through the exhaust duct 37 to stack 35, it being understood that valves 39 and 36 are partially opened for this While the furnace is in this condition valve 33 partially open. That fraction of the gases which pass into chamber 11 for pre-heating purposes enters the passage 21 and liows from right to left as viewed in Fig. 2 Vthrough the exhaust duct 30. Y

These gases are drawn `from the duct 30 into the exhaust duct 32 and into Vthe stack 35 by the updraft induced by the stack, it being understood that valves 34 'and 36 are both partially open. When the contents of chamber 10 have been melted and are ready for pouring Sits hydraulic gram isacltuated to' tilt 'chamber 10 Ainto a above that required to recirculate and oyer and above 2,940,744. A ,Y i"

4 1 position wherein slag' can be poured from 4the spout17 and then, after the slag has been poured, the molten metal may be poured from the spout. The aperture in the Wall of the chamber leading tothe spout is normally closed by a temporary tireclay plug in accordance with conventional practice while the co'ntents of 4chamber 1'0 are being rendered molten. Y

When the contents of chamber 10 has been poured the charge in chamber 11 will.` have reached its fully preheated condition or substantiallyso.` Chamber 10 is quickly recharged and burner 22 is-removed and 'replacedV by a door. Burner 23 is applied to the outer' end of end: Wall 19a and is ignited.V This burner discharges in a reverse direction or from right to left asviewed in Fig. 2, and the heat generated therefro'm is utilized to bring the pre-heated Vcharge in chamber 11 to a molten con- Vcentral partition 12 throughV duct 30 to passage 21 and removal of these gases to the stack is prevented by closing valve 34. YAnotherrportion of the hot gases passes the partially open valve 28 through'chamber 10 which n is now being utilized as a pre-heating chamber to`preheat the charge therein. These gases on .reaching passage 20 flow downwardly and into duct 29 from which they may pass to the stack through exhaust duct31. In this position Yo'f operation valve 33 is partially open, permitting flow to the stack through the exhaust duct'.v Valve 39 is closed and valve/40 partially opened to permit flow of excess of hot gases from Ypassage 27 Ydirectly to the st ack 35; n Y Y The improved furnace may be advantageously used to produce steel Vdirectly from iron ore, or it may be utilized advantageously where the charge is composed partially of iron ore and partially of scrap. It may' alsobe used for melting the metallic contents of variousV other ores.

As the return ducts 29V and 30, respectively, are relatively short and serve to return quickly a substantial fraction o'f the hot gases developed bythe burners to the outer ends of their respective chambers, the heat available in these hot Vgases is most advantageously utilized. These gases'being rather rich in carbon monoxide tend to contribute Vto the maintenance of a reducing atmosphere in the chambers which is essential to reduction oxides. As there is a large excess of hot gases a portion of these gases is transmitted to the other chamber for the purpose of pre-heating the contents thereof and the excess of hot gases is allowed to escape to the stack directly. The valves are strategically located to enable properadjustment to' meet variousV conditions.

Various changes may be made in the details of construction without ydeparting from the spirit and scope of the invention as defined by the appended claims..

I'claim: Y Y Y Y 1. A smelting furnace comprising means providing tWo Ysrnelting chambers arranged in end to end relation each of which is oscillatableindependently of the other, heating means :for each chamber located adjacent Vtherouter end thereof, means for'returning a portionof the hot gases generated by the heating means `from adjacentrthe inner end of each chamber to the outer end thereof for recirculating through the chamber, means adjacent the inner ends of the chambers for conductinga portion of the gases from thechamber being heated through the other chamber to preheat the contents thereof, a stack, and means for optionally connecting the stack to the returning means of each chamber. Y'

2. A smelting furnace comprising meansv providing two smelting chambers arranged in end to end relation each of which is oscillatable independentlyY of the other, heating means for each chamber Varranged to discharge therein from adjacent its Youter end, a recirculating duct .for .each chamber communicating with the vinner end thereof and the outer end thereof, a stack, exhaust ducts connecting the recirculating products to the stack, and means for controlling the ow of gases from the recirculting ducts through the exhaust ducts to the stack.

3. A smelting furnace comprising means providing two smelting chambers arranged in end to end relation each of which is oscillatable independently of the other, heating means for each chamber arranged to discharge therein from adjacent its outer end, a recirculating duct for each chamber communicating with the inner end thereof and the outer end thereof, a stack, exhaust ducts connecting to the recirculating products to the stack, means for controlling the flow of gases from the recirculating ducts through the exhaust ducts to the stack, and additional exhaust ducts communicating with the inner ends of the chamber and with the stack, and means for controlling the ow of gases through said additional exhaust ducts.

4. A smelting furnace comprising means providing two smelting chambers arranged in coaxial alignment each of which is oscillatable independently of the other, means for heating each chamber from adjacent the outer end thereof, return ducts communicating with the inner ends of said chambers for returning portions of the hot gases from each chamber to the outer end thereof, means for regulating the ow from the inner end of one chamber into the inner end of the other, a stack, exhaust ducts connecting the recirculating ducts to the stack, and means for regulating the ow through said exhaust ducts.

5. A smelting furnace comprising means providing two smelting chambers arranged in coaxial alignment each of which is oscillatable independently of the other, means for heating each chamber from adjacent the outer end thereof, return ducts communicating with the inner ends of said chambers for returning portions of the hot gases from each chamber to the outer end thereof, means for regulating the flow from the inner end of one chamber into the inner end of the other, a stack, exhaust ducts connecting the recirculating ducts to the stack, means for regulating the flow through said exhaust ducts, and additional exhaust ducts connecting the inner ends of the chambers to the stack, and means for regulating the flow through said additional exhaust ducts.

6. A smelting furnace comprising means providing two smelting chambers arranged in coaxial alignment each of which is oscillatable independently of the other, means for heating each chamber adjacent its outer end, return ducts communicating with the inner ends of said chambers for returning portions of the hot gases from each chamber to the outer end thereof, means between the return ducts for permitting but regulating ow from the inner end of one chamber into the inner end of the other chamber whereby a portion of the hot gases generated in either chamber will be returned to the outer end thereof, and the remainder of such hot gases will be permitted to pass into the other chamber to pre-heat the contents thereof.

References Cited in the le of this patent UNITED STATES PATENTS 817,099 Benjamin Apr. 3, 1906 

